1. Field of the Invention
The present invention generally relates to a card type device and a host using the same. In particular, the present invention relates to a card type device serving as a supplemental battery in addition to performing its basic functions, and a host using the same.
2. Description of the Related Art
Generally, a card type device, such as a PCMCIA card, in accordance with the Personal Computer Memory Card International Association (PCMCIA) standard like PCMCIA Spec. 2.1 or a CF card in accordance with the Compact Flash (CF) standard like Compact Flash Spec. 1.4, is connected to portable devices, e.g., laptop computers, for the purpose of expanding functions of the portable devices, such as providing input/output or supplementary storage, for example. The manufacturers of such card type device and the manufacturers who use such card type devices specified particular rules in relation to the physical/electrical format between the two types of devices, e.g., data format and data interfacing, and have been manufacturing products according to such particular rules, thereby enabling one card type device to be compatibly used in various types of devices.
Specifications for the card type devices include the specification for power supply, and FIG. 1 schematically shows a conventional power interface between a host and a PCMCIA/CF card. Referring to FIG. 1, the PCMCIA/CF card 20 is provided with a PCMCIA/CF controller 14 and a ground GND for supplying power VCC from a power supply 12 of the host 10. In other words, the specification for the conventional PCMCIA/CF card 20 specifies that the power be supplied from the host 10 to the PCMCIA/CF card 20 for the input/output operations or reading/writing operations of the PCMCIA/CF card 20. According to the specification, the PCMCIA/CF card 20 is constructed to operate simply as an input/output card or a memory. FIG. 2 is an illustration of an exploded perspective view of the conventional CF card, and FIG. 3 is an illustration of a perspective view showing a frame of the conventional PCMCIA card.
However, there are considerable problems with this conventional power supply specification between the host 10 and the PCMCIA/CF card 20. One of these problems is that since the power is supplied only from the host 10 to the PCMCIA/CF card 20, the power is consumed relatively fast when the card type device is used. For example, when the PCMCIA/CF card 20 is used in portable devices like a personal digital assistant (PDA), as the power is used for the PCMCIA/CF card 20, the battery of the PDA is consumed rapidly. As a result, use time of the host becomes shortened.
Considering the fact that there have been an increasing number of telephone and data communication functions added to portable devices like PDAs, it is expected that the power consumption of the portable devices will greatly increase. Accordingly, a battery of large capacity will be required for the portable devices.